4.4-stable review patch. If anyone has any objections, please let me know.
------------------ From: Bjorn Andersson <[email protected]> commit 30acf549ca1e81859a67590ab9ecfce3d1050a0b upstream. For dm uarts in pio mode tx data is transferred to the fifo register 4 bytes at a time, but care is not taken when these 4 bytes spans the end of the xmit buffer so the loop might read up to 3 bytes past the buffer and then skip the actual data at the beginning of the buffer. Fix this by, analogous to the DMA case, make sure the chunk doesn't wrap the xmit buffer. Fixes: 3a878c430fd6 ("tty: serial: msm: Add TX DMA support") Cc: Ivan Ivanov <[email protected]> Reported-by: Frank Rowand <[email protected]> Reported-by: Nicolas Dechesne <[email protected]> Signed-off-by: Bjorn Andersson <[email protected]> Acked-by: Andy Gross <[email protected]> Tested-by: Frank Rowand <[email protected]> Reviewed-by: Stephen Boyd <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> --- drivers/tty/serial/msm_serial.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/drivers/tty/serial/msm_serial.c +++ b/drivers/tty/serial/msm_serial.c @@ -726,7 +726,7 @@ static void msm_handle_tx(struct uart_po return; } - pio_count = CIRC_CNT(xmit->head, xmit->tail, UART_XMIT_SIZE); + pio_count = CIRC_CNT_TO_END(xmit->head, xmit->tail, UART_XMIT_SIZE); dma_count = CIRC_CNT_TO_END(xmit->head, xmit->tail, UART_XMIT_SIZE); dma_min = 1; /* Always DMA */
